Rare Instance and Pathophysiological Insights of Thrombotic Thrombocytopenic Purpura Following Pacemaker Implantation

This is the case of a 71-year-old female with past medical history of atrial fibrillation status post ablation 2 months ago currently on apixaban, hypothyroidism, remote history of breast cancer treated with radiation therapy and mastectomy, thyroid cancer status post thyroidectomy, and non-hodgkin's lymphoma (marginal zone lymphoma) treated with bendamustine and rituximab chemotherapy in 2019 followed by rituximab maintenance through 2021. She initially presented with a 4-day history of progressively worsening weakness and altered mental status. She was noted to have significant expressive aphasia and was only oriented to person on admission. Eight days before admission, the patient had a pacemaker placed which she tolerated well. She denied any facial droop, facial weakness, or difficulty walking. She also endorsed a 4-day history of diarrhea with red-tinged bowel movements but denied associated abdominal pain, frank blood or melena. Stroke workup was initiated and CT head was negative for acute findings. Labs revealed a hemoglobin of 11.4, platelet count of 16,000, GFR of 48, and bilirubin of 4.4. Coagulation studies and fibrinogen studies were within normal limits. LDH was elevated to 1019 and haptoglobin was low. ADAMTS 13 level was ordered, and the patient was subsequently started on high-dose steroids (solumedrol 1g daily) as well as plasma exchange with FFP transfusion due to concerns of thrombotic thrombocytopenic purpura (TTP). After the initiation of treatment, the patient had an uptrend in her platelets and resolution of neurologic symptoms. Repeat labs showed ADAMTS13 of < 2.0 confirming the diagnosis of TTP. Thrombotic thrombocytopenic purpura (TTP) following pacemaker implantation is a rare but potentially life-threatening complication. The pathophysiology of TTP involves the formation of microthrombi in small blood vessels leading to thrombocytopenia, hemolytic anemia, and organ damage. This condition is typically associated with a severe deficiency of ADAMTS13, a protease responsible for cleaving large von Willebrand factor (vWF) multimers. During pacemaker implantation, endothelial injury and increased shear stress promotes the release and accumulation of large vWF multimers, which leads to widespread microthrombosis in the presence of an ADAMTS13 deficiency. The incidence of TTP after pacemaker implantation is extremely low, with few cases reported in the literature. This rarity underscores the importance of recognizing this potential complication as timely diagnosis and treatment with plasma exchange can be lifesaving. Other potential causes of TTP include autoimmune disorders (e.g. systemic lupus erythematosus), infections, certain medications (e.g., quinine, ticlopidine, clopidogrel), malignancies, and pregnancy. In these cases, the underlying pathophysiological mechanisms often involve the production of autoantibodies against ADAMTS13, leading to its functional deficiency and subsequent microthrombi formation.